Search Publications
Spatial scale of high-speed flows in the plasma sheet observed by Cluster
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
Spatial gradients of high-speed flows in the midtail plasma sheet are determined using multipoint observations from the Cluster spacecraft along the ``dawn-dusk'' direction (perpendicular to the main flow and in the plane of the tail current sheet) and along the north-south direction. If we take the average or median of the spatial gradients and a…
Cluster observations of earthward flowing plasmoid in the tail
Balogh, A.; Glassmeier, K. -H.; Zhang, H. +10 more
The energetic electrons and ions embedded in Earthward-moving plasmoid structures have been observed. These plasmoids are associated with a rotational local Bz component (bi-polar) signature. Energetic electrons are found to be confined in a smaller spatial region than ions inside the plasmoid. Energetic ions and electrons seem to be a …
Orientation and propagation of current sheet oscillations
Sauvaud, J. -A.; Balogh, A.; Zhang, T. L. +6 more
Using the four-spacecraft Cluster system, we analyze rapid neutral sheet crossings near the Cluster apogee at about -18RE. In case studies of multiple oscillations of the locally quiet plasma sheet as well as in a statistical study of oscillations in dawn and dusk near-flank plasma sheet portions we typically obtain that locally these d…
A microscopic and nanoscopic view of storm-time chorus on 31 March 2001
Gurnett, D. A.; Pickett, J. S.; Santolík, O. +2 more
We investigate intense whistler-mode chorus emissions which occurred during the geomagnetic storm on 31 March 2001. We use multipoint measurements obtained by the Cluster spacecraft in the premidnight equatorial region outside the plasmasphere at a radial distance of 4 Earth radii (L = 4.0 - 4.2). Observed spatio-temporal variations of the directi…
Cluster observations of lower hybrid turbulence within thin layers at the magnetopause
Wahlund, J. -E.; Fazakerley, A. N.; André, M. +3 more
We use data from the Cluster satellites to study waves in the frequency range of ~2-150 Hz at the magnetopause. In addition to broad band wave turbulence we identify lower hybrid drift waves and whistler waves. Wave amplitudes maximize within narrow current sheets that are associated with density gradients and electron beams and that can be the se…
Anatomy of a flux transfer event seen by Cluster
Hasegawa, H.; Paschmann, G.; Sonnerup, B. U. Ö.
Data from Cluster are used to study the structure of a flux transfer event (FTE), seen near the northern cusp. We employ Grad-Shafranov reconstruction, using measured fields from all four spacecraft to produce a map of the FTE cross section. The FTE consists of a flux rope of approximate size 1RE and irregular shape, embedded in the mag…
Nonlinear guiding center theory of perpendicular diffusion: General properties and comparison with observation
Qin, Gang; Matthaeus, W. H.; Shalchi, Andreas +1 more
A nonlinear guiding center (NLGC) theory for diffusion of charged particles perpendicular to the mean magnetic field was recently proposed. Here, we draw attention to a number of attractive features of this theory: (1) The theory provides a natural mechanism to connect the perpendicular mean free path with the parallel mean free path. In fact, the…
Thin electron-scale layers at the magnetopause
Fazakerley, A. N.; André, M.; Vaivads, A. +2 more
We use data from the four Cluster satellites to examine the microphysics of a thin electron-scale layer discovered on the magnetospheric side of the magnetopause. Here the ion and electron motions are decoupled in a layer about 20 km (a few electron scales) wide, including currents and strong electric fields. In this layer the electrons are E × B …
Tracking a major interplanetary disturbance with SMEI
Price, S.; Simnett, G. M.; Webb, D. F. +14 more
We present the first clear observations of an Earth-directed interplanetary disturbance tracked by the Solar Mass Ejection Imager (SMEI). We find that this event can be related to two halo CMEs seen at the Sun about 2 days earlier, and which merged in transit to 1 AU. The disturbance was seen about 16 hours before it reached Earth,and caused a sev…
Multi-fluid simulations of Ganymede's magnetosphere
Paty, Carol; Winglee, Robert
Comparative studies of 3D multi-fluid simulations with Galileo magnetometer data are used to develop a quantitative model of the currents and fields within Ganymede's magnetosphere as well as its bulk plasma environment. The model includes contributions from Jupiter's magnetosphere and the flux of different ion species originating from Ganymede's …